JPH05142385A - Cleaning device for fuel assembly - Google Patents

Abstract

PURPOSE:To quickly and surely clean the inner and outer surface of a fuel assembly used at a nuclear power station, in a fuel pool, and prevent contaminants from being diffused within the pool. CONSTITUTION:A guide rail 2 is provided in a cleaning cylinder 1, and a fuel lift means 3 is then disposed in the guide rail 2. And an ultrasonic wave cleaning means 4 and a watering block 5 are disposed in a position roughly at the center of the cleaning cylinder 1. A drive means 6 is concurrently provided for at least, either one of the ultrasonic wave cleaning means 4 and the watering block 5, and the upper and the lower position of both of them is so constituted as to be relatively moved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cleaning device for cleaning a fuel assembly used in a nuclear power plant, and more particularly to an ultrasonic cleaning device and a water spray block for water jet cleaning.
Concerning what you have at the same time.

[0002]

2. Description of the Related Art Nuclear fuel in a nuclear power plant is manufactured by packing pellets of nuclear fuel material in an elongated cladding tube.
Is formed, and a large number of fuel rods 35 are assembled in parallel by a spacer and an upper tie plate 36 and a lower tie plate 37 at a slight interval to form a fuel bundle. The fuel bundle configured as described above is covered with a rectangular tube-shaped channel box 34 around the periphery, and is loaded into the core as the fuel assembly 21. And after being used for a predetermined period,
It is taken out of the core again and inspected and maintained appropriately. At this time, since the inner and outer surfaces of the fuel assembly 21 are contaminated with the clad containing the radioactive material, it is necessary to clean it.

The cleaning of the fuel assembly 21 as described above is performed inside the tubular body standing in the fuel pool to prevent contaminants from flowing out to the fuel pool. The conventional cleaning of the fuel assembly 21 is performed by using a water jet while lifting the lifting hook 33 at the upper end of the fuel assembly 21 by a crane and moving it up and down. Note that ultrasonic cleaning may be performed in addition to the water jet.

[0004]

In the conventional fuel assembly cleaning apparatus, a fuel jet is used to move the fuel assembly up and down by using a crane inside the cleaning cylinder, and therefore, one fuel assembly is used. There is no choice but to lengthen the body washing time. Therefore, there has been a demand for a fuel assembly cleaning device that is highly efficient and capable of complete cleaning.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide an efficient cleaning device capable of reliably cleaning the inner and outer surfaces of a fuel assembly in a short time. To take. The cleaning device has a cleaning cylinder having a length that is at least twice the length of the fuel assembly, and the fuel elevating device is guided by a guide rail provided inside the cleaning cylinder. This fuel elevating / lowering device elevates and lowers by supporting at least an upper end portion and a lower end portion of a fuel assembly. Further, the ultrasonic cleaning device and the water spray block are arranged at positions that surround the outer periphery of the fuel assembly at the longitudinally intermediate portions of the respective cleaning cylinders. Then, at least one of the ultrasonic cleaning device and the water spray block is provided with a driving means, whereby the vertical position of both is relatively moved.

[0006]

As shown in FIGS. 1 and 2, the fuel assembly 21 is mounted on the fuel elevating device 3 which is guided by the guide rail 2 and moves up and down. Then, the fuel lifting device 3 is positioned in the lower cleaning cylinder 8 and the ultrasonic cleaning device 4 is operated. At this time, the sprinkling block 5 is positioned below the cleaning unit 20 by the driving means 6. When the ultrasonic cleaning device 4 operates, ultrasonic vibrations are simultaneously transmitted to the water contacting the inner and outer surfaces of the channel box 34 (FIGS. 9 and 10) of the fuel assembly 21 and the water around the fuel rods 35.
In this state, the fuel elevating / lowering device 3 is guided by the guide rails 2 and raised at a constant speed. The pump 25 is driven prior to ultrasonic cleaning, and the contaminants in the cleaning cylinder are guided to the cartridge filter and captured. When the ascending of the fuel assembly 21 is completed, the ultrasonic cleaning is completed.

Then, the channel box 34 of the fuel assembly 21 is removed, and the fuel assembly 21 is again held by the fuel elevating device 3 in the lower cleaning cylinder 8. Further, as the pump 25 is driven, the water sprinkling block 5 is lifted by the driving device 6 and is positioned above the cleaning unit 20. Then, the washing water is vigorously ejected from the plurality of nozzles provided inside the water spray block 5. Therefore, the fuel elevating device 3 is raised, and when it reaches the upper end, cleaning with the water jet is completed. At this time, the contaminants that have flowed out into the cleaning cylinder 1 are captured by the cartridge filter 19 (FIG. 7).

[0008]

Embodiments of the present invention will now be described with reference to the drawings. FIG. 1 is a partial vertical sectional front view of a cleaning apparatus of the present invention,
FIG. 2 is a side view of the same, and FIG. 3 is a partially cutaway perspective view showing a main part of the apparatus. In addition, FIG. 4 is an explanatory view of the watering block 5,
5 is a vertical sectional view of the fuel guide 9, FIG. 6 is a partially cutaway plan view thereof, FIG. 7 is an overall perspective view of the present apparatus, and FIG. 8 is the same plan view. The overall configuration of this cleaning device is configured as shown in FIGS. 7 and 8. And this device is installed in the fuel pool of a nuclear power plant. That is, the base 15 at the lower end of the device is installed on the bottom of the pool,
A cleaning cylinder mount 16 and a filter mount 18 are erected on the cleaning cylinder mount 15, and the cleaning cylinder 1 is fixed to the cleaning cylinder mount 16. This washing cylinder 1
Consists of an upper cleaning cylinder 7 and a lower cleaning cylinder 8. Then, the lower cleaning cylinder 8 is fixed to the cleaning cylinder base 16, and the lower end of the upper cleaning cylinder 7 is fixed to the upper end of the lower cleaning cylinder 8. Next, a cartridge filter 19 is attached to the filter mount 18. Further, as shown in FIG. 8, two pumps 25 having different capacities are fixed on the base, and these pumps 25 are connected to the lower end of the washing cylinder 1 and the cartridge filter 19 by a pipe 26.

A gate 41 is provided on one side of the upper cleaning cylinder 7 and is opened / closed by a manual operation of an opening / closing lever 32. The upper and lower ends of the upper cleaning cylinder 7 are open, and the openings are connected to the upper end opening of the lower cleaning cylinder 8.
The upper end of the upper cleaning cylinder 7 is raised above the water surface of the fuel pool. The cross section of the upper cleaning cylinder 7 is formed in a rectangular shape. Next, the lower cleaning cylinder 8 is formed in a rectangular cross section with an enlarged upper end, and a cleaning unit 20 is provided at the upper end. Guide rails 2 are provided on one side of the inner surfaces of the lower cleaning cylinder 8 and the upper cleaning cylinder 7, respectively, and the fuel elevating device 3 shown in FIG. That is, the fuel elevating / lowering device 3 has an elongated frame, and a guide block that engages with the guide rail 2 is provided at an appropriate position thereof. This fuel lifting device 3
At the lower end of the finger spring protection cylinder 10 is opened upward, and the lower support device 11 is provided in the finger spring protection cylinder 10. A fuel guide 9 is arranged at the upper end of the fuel lifting device 3. As shown in FIGS. 5 and 6, the fuel guide 9 is formed in a rectangular funnel shape with its upper end widened, and guide rollers 13 are rotatably supported on the four sides of the inner surface of the lower portion thereof. Further, air cylinders 14 are provided at the corners, respectively, and an angled guide portion 31 is provided at the tip of the air cylinder 14.

Next, in the cleaning section 20 formed at the upper end of the lower cleaning cylinder 8, the sprinkling block 5 and the ultrasonic cleaning device 4 are arranged. The central axis of the water spray block 5 is aligned with the axes of the fuel guide 9 and the lower support device 11. Then, the water spray block 5 is moved up and down by a pair of driving means 6 composed of cylinders, which is guided by the guide shaft 27. A large number of nozzles 12 are provided on the inner peripheral surface of the watering block 5. A pipe (not shown) for introducing cleaning water is connected to the nozzle 12. Next, the ultrasonic cleaning device 4 is located inside the cleaning unit 20 and is placed outside the water spray block 5.
~ 4 are attached. Next, a pipe 26 is connected to the lower end of the lower washing cylinder 8 and is connected to the submersible pump and the cartridge filter. A hoisting device 29 is provided at the upper end of the cleaning cylinder 1, and the fuel elevating device 3 is supported by the elevating wire 24 so as to be vertically movable.

The role of each component will be described next. First, when the water spray block 5 cleans the fuel assembly, the upper cleaning cylinder prevents diffusion of the clad that rolls up with the cleaning, and directly below the water surface. For the purpose of supplying the highly-dissolved oxygen water to the device, the gate 41 is opened and closed to guide the fuel assembly into the device. Next, the fuel guide 9 has a guide surface for facilitating attachment / detachment of the fuel assembly to / from the fuel elevating / lowering device 3, and has a fuel assembly inside thereof.
A guide roller 13 is provided to prevent damage to the outer circumference of 21. Further, when the channel box 34 of the fuel assembly is removed, a gap is created between the guide roller 13 and the fuel assembly, so that the air cylinder 14 (FIG. 6) causes the guide portion 31 to protrude to allow fuel assembly. Prevent the body from shaking. Next, in the ultrasonic vibration device 4, a completely sealed vibrator is attached at a position 100 mm away from the surface of the fuel assembly. The vibrator is detachably held on the mounting plate and can be easily replaced in the event of a failure.

The sprinkling block 5 is formed in a short cylindrical shape with an inner peripheral surface of a rectangular shape, and eight nozzles 12 in two stages, four on each side and four on each side, are arranged at an angle of 30 degrees downward as shown in FIG. There is. This orientation of the nozzle 12 prevents the clad from rolling up during cleaning. The fuel elevating / lowering device 3 is a device for vertically moving the fuel assembly at a constant speed during ultrasonic and water jet cleaning. This means that when the upper cleaning cylinder 7 and the lower cleaning cylinder 8 are connected, each pair of guide rails 2 is extended linearly. Then, it is guided by the guide rail 2 to move up and down. The vertical movement distance is 3900 mm, for example. Next, the finger spring protection cylinder 10 is a protection cylinder for preventing the finger spring of the fuel assembly from being detached if the finger spring of the fuel assembly is washed with a strong water pressure at the time of washing with a water jet. Further, the lower support device 11 has a structure in which a hollow cylinder is erected, and the upper surface is 45
There is a chamfered portion on which the lower tie plate 37 (FIG. 9) of the fuel assembly is placed. This lower support device 11
The clad, which is communicated with the submersible pump and separated from the fuel assembly 21, is guided to the cartridge filter 19.

Next, a method of using this device will be described.
The fuel assembly 21 (Fig. 9, Fig. 1
0) has its lifting hook 33 supported and passes through a gate of a cask pit (not shown). Therefore, the gate 41 (FIG. 7) of the upper cleaning cylinder 7 of the main cleaning device is manually opened, and the fuel assembly is guided into the upper cleaning cylinder 7 by the above fuel exchanger. Next, the fuel exchanger is lowered, and the fuel assembly 21 is attached to the fuel elevating / lowering device 3 located below. After the mounting of the fuel assembly 21 is confirmed, the refueling machine is moved up and moved outside the apparatus. Next, the upper washing cylinder 7
The gate 41 is closed and the smaller pump 25 (FIG. 8) is driven. The water supply capacity of this pump 25 is, for example, 5 m ³
/ Hr. The ultrasonic cleaning device 4 is driven together with the driving of the pump 25. In this state, the fuel lifting device 3 is raised. Then, the channel box 34 of the fuel assembly 21
The water on the inner and outer surfaces of and the water on the outer periphery of the fuel rod 35 vibrate ultrasonically,
The clad adhering to the surface peels off. The separated clad is gently guided downward by the smaller pump 25,
It is captured by the cartridge filter 19. At this time, the sprinkling block 5 should be arranged so as not to interfere with the ultrasonic vibration as shown in FIG.
As described above, the ultrasonic cleaning device 4 is held at a lower position. When the ultrasonic cleaning device 4 is driven, the water spray block 5 does not spray water. This is because it hinders ultrasonic cleaning. When the lifting of the fuel assembly 21 is completed by the fuel elevating device 3, the ultrasonic cleaning is finished, and the ultrasonic cleaning device and the pump are
25 is stopped.

Next, the cap screw 39 in FIG.
Is removed from the bar-shaped protrusion 40 of the upper tie plate 36,
The channel box 34 is supported by a channel box handling jig (not shown). Therefore, the channel box 34 is removed from the fuel assembly 21 by lowering the fuel elevating device 3. The removed channel box 34 is conveyed to the outside of the apparatus from the upper cleaning cylinder 7 having the gate 41 (FIG. 7) opened. Therefore, next, the gate 41 is closed and the larger pump 25 (FIG. 8) is driven. The water supply capacity of the pump 25 is, for example, about 120 m ³ / Hr. Then, the water supply pump of the watering block 5 is driven. Further, the air cylinder 14 of the fuel guide 9 is driven, and the guide portion 31 is slightly projected. In this state, the fuel lifting device 3
To raise the fuel assembly 21. When the lifting of the fuel assembly 21 is completed, the cleaning with the water jet is completed. Therefore, the fuel elevating device 3 is lowered again, and then it is raised to remove the channel box previously removed.
34 is attached to the fuel assembly 21, and the cleaning work is completed.

[0015]

According to the cleaning apparatus of the present invention, ultrasonic cleaning and cleaning with a water jet can be performed in the same cleaning cylinder 1. That is, by mounting the fuel assembly 21 on the fuel elevating device 3 and elevating the fuel elevating device 3, both washings can be efficiently performed. Therefore, a quick and efficient cleaning operation can be secured without polluting the fuel pool. Further, at least one of the ultrasonic cleaning device 4 and the sprinkling block 5 is provided with the driving means 6 so that the vertical positions of the both are relatively moved. Therefore, when the ultrasonic cleaning device 4 is operated, the sprinkling block is operated. 5 can be moved. As a result, the ultrasonic cleaning device 4 can efficiently clean the fuel assembly 21 without being disturbed by the sprinkling block 5. Further, when the water spray block 5 is operated, it can be positioned at substantially the same height as the ultrasonic cleaning device 4, and the fuel assembly 21 can be cleaned thoroughly from the upper end to the lower end. The cleaning unit 20 including the ultrasonic cleaning device 4 and the sprinkling block 5 can be made into a small space, and the cleaning device can have a small space as a whole.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional front view of the cleaning device.

FIG. 2 is a vertical sectional side view of the cleaning device.

FIG. 3 is a perspective view of a main part of the cleaning device.

FIG. 4 is an explanatory view of a sprinkling block 5 of the present cleaning device.

FIG. 5 is a vertical cross-sectional view of a fuel guide 9 of the present cleaning device.

FIG. 6 is a partially cutaway plan view of the fuel guide 9.

FIG. 7 is an overall perspective view of the cleaning device.

FIG. 8 is a plan view of the same.

FIG. 9 is a partially cutaway perspective view of a fuel assembly 21 which is a target of the present cleaning device.

FIG. 10 is a schematic exploded perspective view of the fuel assembly 21.

[Explanation of symbols]

 1 Cleaning Cylinder 2 Guide Rail 3 Fuel Elevating Device 4 Ultrasonic Cleaning Device 5 Water Sprinkling Block 6 Drive Means 7 Upper Cleaning Cylinder 8 Lower Cleaning Cylinder 9 Fuel Guide 10 Finger Spring Protective Cylinder 11 Lower Supporting Device 12 Nozzle 13 Guide Roller 14 Air Cylinder 15 Base 16 Washing cylinder mount 18 Filter mount 19 Cartridge filter 20 Washing part 21 Fuel assembly 22 Water surface 23 Fuel pool 24 Lifting wire 25 Pump 26 Pipe 27 Guide shaft 28 Piston rod 29 Hoisting device 30 Working platform 31 Guide part 32 Opening and closing Lever 33 Lifting hook 34 Channel box 35 Fuel rod 36 Upper tie plate 37 Lower tie plate 38 Flange 39 Cap screw 40 Rod-like protrusion 41 Gate

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shoichi Yokogawa 3-7-1, Nishishimbashi, Minato-ku, Tokyo, within Toshiba Plant Construction Co., Ltd. (72) Inventor Hitoshi Sakai 8 Shinsugita, Isogo-ku, Yokohama, Kanagawa Toshiba Yokohama Works Isogo Engineering Center (72) Inventor Shiro Furumura 8 Shinsugita, Isogo-ku, Yokohama-shi, Kanagawa Prefecture Yokohama Works Isogo Engineering Center (72) Inventor Shigehiro Oka Horikawa-cho, Kawasaki-shi, Kanagawa Prefecture 66-2 Toshiba Engineering Co., Ltd. (72) Inventor Kazunori Kamiyama 1-4-1, Egawa, Kawasaki-ku, Kawasaki-shi, Kanagawa Ebara Kogyo Co., Ltd. (72) Isao Akimoto 6606 Fukaya, Ayase-shi, Kanagawa Oyama Industrial Co., Ltd.

Claims (1)

[Claims] 1. A cleaning cylinder (1) having a length that is at least twice as long as a fuel assembly, and a guide rail (2) provided inside the cleaning cylinder (1) to guide the fuel assembly. A fuel elevating device (3) for elevating and lowering while supporting at least an upper end portion and a lower end portion thereof, and a super-position disposed at a position that surrounds an outer periphery of the fuel assembly at an intermediate portion in a longitudinal direction of each of the cleaning cylinders (1). A drive means (provided on at least one of the ultrasonic cleaning device (4), the water spray block (5), and the ultrasonic cleaning device (4) and the water spray block (5) to relatively move the vertical position of both. 6) A cleaning device for a fuel assembly, comprising: